Earlier quoted context omitted.
I don't think so, because HBO's old content is already widely available. It's only kind of good for retention, and that only on HBO Go (and Amazon, now that it's there too). The competition for new subscriptions and paying that one more month always takes place in the present/future, or at least for content you haven't watched yet which for any fan is going to be present/future. And Netflix is kicking ass there, TBH.…
You're assuming fans only care about fresh content and have seen everything in the past. Thats not true.
Sure. But then you come back to the fact that the majority of their old, good content is carried on other services.